This project was initiated to clarify biochemical receptor mechanisms for dopamine in the mammalian brain and to develop a better understanding of the mechanism of action of drugs used in the treatment of Parkinson's disease. Topics pursued in the current year include: 1) the evaluation of the activity of lergotrile as an agonist in the dopamine-sensitive adenylyl cyclase system; 2) the development of a sensitive radioisotopic enzymatic assay for apomorphine, a dopaminergic agonist; 3) the evaluation of the distribution of apomorphine within discrete regions of the mammalian brain; and 4) the preparation of a major review of the biochemistry and physiology of cyclic nucleotdes in the nervous system. BIBLIOGRAPHIC REFERENCES: Kebabian, J.W.: The Biochemical Regulation and Physiological Significance of Cyclic Nucleotides in the Nervous System. In Greengard, P. and Robison, G.A. (Eds.): Advances in Cyclic Nucleotide Research. New York, Raven Press, 1977, pp. 421-508.